Improved machine for milling the knife-edges of scale-beams



@sindv gitana @anni @Wina Lena-s 'Patent No. 95,729, laad caoba- 12,1869. f

The Schedule referred to in these Letters Patent and making part of the same.

To all whom it may concern Be it knownthat I, THOMAS J. RocKwooD, of St. Johnsbury, in the county of Gall donia, and State of Vermont, have invented certain newV and useful Im provements in Machines for Milling the Knife-Edges of Scales; and I do hereby declare that the following is a full and exact description thereof.

My invention is more especially intended to apply to the machines described in the patent issued to me, dated August 11,1868, but may be used in connection with various modifications ot' mechanism for millingr knife-edges, which are not desciibed in said patent.

My invention facilitates the placing and properly holding ofthe levers.

It frequently happens, in spite of all the care taken in moulding, that levers are warped, bent, twisted, and variously contorted, to small extents, and although the milling-operation is adapted to remove enough of the material of the knife-edges, and the knife-edges are made suiiiciently too large, in the iirst instance; to insure 4that the iinal result shall leave the finished knifeedges with their working angles in exactly the proper positions, the distortion of the general casting in which they are placed embarrasses the operation of properly mounting the lever in the machine.

In all this kind of work, we mount the lever twice. In the n'rst instance, we adjust the position by means of vthe central knife-edges, resting them in notched bars. Having thus placed it, and taken a very iirm hold of the ends ot' the lever, we proceed to mill the knife-edges at the ends, irstl treating those at one end, and then those at the other end of the lever. After having thus treated the ends of a lot of levers, we set them on another machine. In this second machine, we set the levers in position by the aid ofthe now liinished knife-edges, and mill the central knife-edges. In order to leave no material to be milled in the central knife-edges, we place the rests in which they are mounted at iirst a little low. In other words, we tin ish the end knife-edges with the central knife-edges in a slightly falseV position, then afterward holding the beam exactly right, by the4 aid of the now nicely-linished end knife-edges, we again take a firm hold of the lever, and treat the central knife-edges, removing just enough to bring them into their exactly right position.

his, which I have now described, is the part ofthe old process 'to which my present invention relates. In the old practice, the entire lever was iinished in the plane in which the central knife-edges happened to stand; that is to say, the central knife-edges were assumed, at tirst, to be right, or,-rather, to be to an equal extent below the .proper position, andthe `entire lever was necessarily finished in that plane.

Now the central knife-edges are as liable as either of the others to be slightly misplaced, and the general plane of the entire lever should evidently be the influential plane. In other words, in case the lever is twisted, or otherwise distorted, we should strike an average position with the knife-edges, and finish them in the position to which the end levers are already nearly adapted, and removes the material mainly from the central knife-edge, which is too much depressed.

I accomplish this by providing yielding supports, in which thecentral knife-edges are rested for the rst operation.

The supports are very firmly guided, so that they can only move vertically; but they may sinli to any required degree, one below the other, and both may go below or remain above their old position, as required by the twisting or other distortion of the lever.

I have provided, also, several othermodiiications in the mechanism, which render the holding and milling ofthe parts more mathematically exact, or more easy of accomplishment. f

I will now proceed to describe what I consider the best means of carrying out my invention, andv will afterward designate the points which I believe to be new.

The accompanying drawings form a part of this speciiication.

Figure l is a central longitudinal section, through a .scale-lever, while mounted on the means for holding it.

It gives an inside view of one of the supports which hold up the central pivots, and shows, in dotted lines, the cam, by turning which such support is made rm.

Figure 2 is a plan View of the same parts. 4The two cams are here represented in dotted lines, one on each side. vv 'f Figure 3 is a cross-section through the centre of the same parts. In this view the cams appear' in strong lines.

of the construction of the rm Vsupports at the ends. They are adjustable in their li'eight.

Figure 5 is a plan view of a modification of" the crosspieces or clamps, which hold down the lever, in which are the knife-edges to be milled.

Similar letters of reference indicate corresponding parts in all the figures.

The drawings represent the novel'parts, witho'nly so much of the ordinary parts as is necessary to indi-` cate their relation thereto.

Figure 4 is a cross-section, showing a modilication;

The parts not represented may be as described in my patent of 1868, above referred to.

There is a exed frame-work of the machine, made, by preference, of cast-iron. This suppprts a carriage, with a table, 85e., as describedin my previous patent, above referred to.

D is a table, capable of traversing, longitudinally, in the vertically-moving carriage, exactly as described in my previous patent.

These, and all other parts of the machine, whether represented or not, will be understood as being made suiciently heavy to avoid any appreciable springing.

Gr G G G are stout blocks or firm supports, ou which rest the ends of the levers, while the end knife-edges are being milled.

. These blocks may be adjustable, outward and inward, to adapt the machine to treat levers of different sizes, or the blocks may be changed for each size or style of beam; but those adjustments or changes will be readily understood without prolonged description.

I will describe them as ixed, which in fact they may be,`during the treatment of a hundred or any other number of levers which are uof uniform size and style.

I have devised a construction by which the upper surfaces of these blocks may be very conveniently adjusted, vertically, within wide limits, when required; but this will be explained further on.

H H are clamps, which are pressed down on the ends of the levers, by means of nuts k, which traverse on screw-threads on the upper end of the fixed rods K.

A coiledspring, k', surrounds each of these rods K, and exerts a constant lifting-force on the clamp or cross-piece H.

The knife-edge is easily liberated by slackening the nut k, and turning the cross-piece H.

In such position, it allows the lever to Vbe readily lifted off, and the cross-piece H, being supported by the spring It', does not fall down, but remains up in position, ready to be immediately turned back into its transverse position, and again screwed down, when a new lever is introduced.

In case the fork at the end of the lever is not sufficiently deep to allow the lever cobe lifted vertically,

when the cross-piece H is turned properly, it can sometimes be liberated bybeing moved-a little endwise, first one way and then the other, to pass the cross-pieces` the ends, which are in the same plane.

This operation can be e'ected b y milling, if preferred, but it is usually done with great facility by hand.

NVe lay each lever on a plain surface, and if it does not rest fair on the four corners, we iile one or another lightly until it does.

Having treated them all in this manner, we are ready to place them, in succession, in the machine, and the four surfaces thus prepared will evidently rest fairly on the four blocks G. This insures the right position of the lever, in one respect. v

This part of the work is performed the same as has been practised with my formerly-patented machine.

Now, to get the lever iu the right position laterally,

it is necessary to rest the central knife-edges in notches,

port it by turning itin the other direction.

in the stout blocks F, and resting them upon springs F2.

The entire blocks F1, with their attachments, may be adjusted to or from each other on the stout transverse way F, and may be held iinnly in any position by means of screw-keys, or the like, not represented.

Now, when a lever is placed in position, so that its surfaces at the ends rest on the four stout posts or` these spring-blocks f, and resting at the ends onlthe four solid blocks G, is with positive certainty in the correct position.

Now, after screwing down the nuts It, and thus depressing the clamping-pieces H very firmly at each end,

I desire to insure a still more firm holding ofthe entire lever, to avoid any trembling, or any motion of any part while the knife-edges at the ends are being milled. Were the central blocks ff rm, I could hold the centre of rhe lever very strongly, by simply introducing at these points such a bolt, K, nut k, cross-piece or clamp `H, and spring 7c. I do employ such parts at the centre, which are not represented, as it may tend to confuse the drawing.

The means for clamping from above in this manner will involve no difculty to any good mechanic, but l employ peculiar means, by which I transform the yielding supports f f instantaneously into solid and very substantial supports to aid in holding the lever very firmly. V

This is eiiected by means of cams y, in the interior of the blocks F1, which are mounted .nu the shaft Y, and turned by the mill-wheel Y1.

readily turned by the thumb-wheel Y, so as to liberate the slide f, by turning it in one direction, and'sup- The cam may act directly against the end-surface of the yielding support f, or it may act thereon through an intermediate pin or block, Y2, as represented.

The` operation of this portion of my invention will ing cross-piece at the centre, not represented, remove i the lever, and giving a half turn, or thereabout, to each of the thumb-wheels Y1, and consequently to the cams y, I set the adjustable supports ff at liberty to move up and down again under the influence of the springs F2 and ofthe friction, whatever it mav be, to whichthey are subject. The force of the springs F should be sucient to overcome the frictionfand to immediately raise the adjustable supports into a position above that which they will assume when a fever is placed in the machine. l Y

Now a new lever is introduced, and again shaken, or turned slightly in one direction or the other, and pressed down upon the yielding supports ff until both, the central knife-edges are received and retained in the lnotches therein. This movement is effected aln ost instantaneously, and immediately thereon the endclamps or cross-pieces H may be set down in place,"

There are two of a these cams, one :for each ofthe blocks F1, and they are4 sented, is applied, and the'lever is ready to have its ends milled and in its turn to be removed.

There nowremains to be described a modiiication which I have invented in the posts G. I can make one alone, or all four of these posts in this manner, so that their height shall be adjustable. Fig. 4 represents this construction.

. Z is a strong and broad support, fastened down adj ust-ably upon a table, I), by means of bolt standing in a slot, as represented.

Z1 is a stout screw, rising from near the centre of the support Z, and threaded for a part or the whole of its height, as` represented.

Z2 is a cap-nut, or adjustable block, adapted, on its under side, to iit upon the screw-post Z1.

Now, by turning the block Z2in one direction or the other, I raise or lower its upper surface, and graduate its elevation to any extent desired, while the parts may` be of such stiffness and strengthas to support the lever the same as a single solid block.

I call the threaded screw Z, and its support, my adjustable block. One will be of some service in connection with three of the iXed blocks G; I prefer, however, to use two; in other words, to replace both of the blocks G at one end by these adjustable blocks. I can employ them at both ends, if necessary, but do not deem it generally expedient. I can employ them with particularly good effect to-support the centre of the milling-machine on which Imill the central knifeedges, after the end knife-edges have been finished.

A very marked advantage comes from the fact that.

the block Z2 ts over and screws down upon the screw Z1, as represented. This arrangement insures that all hips and dirt fall clear, and cannot lodge upon or in the screw.

My block works freely under all conditions, while, if the parts were the other side up, like the common jack-screw employed in lifting weights, it would be liable to be clogged, cut, or abraded with filings and dirt.

Some of the` advantages due to certain features of my invention may be separately enumerated, as` follows:

-First, by reason of the fact that the supports are not permanently fixed, but adj ust themselves vertically, as

Y represented, I cause them to perform the function of determining the correct lateral position of the lever, and of placing it with mathematical,accuracy on the end supports G G G G, while at the same time they allow for a very considerable misplacement of the yet unfinished central knife-edges.

ing with the yielding character of the supports when the leveris being located.

Third, by reason of the fact that my clamps or crosspieces H are held up by coiled springs K?, as represented, I am able to support the cross-pieces in a position-to facilitate the introduction ot' the next lever,

without interfering with the freedom of its movements,

or adding any complicated parts, or subtracting in any degree from the useful qualities ofthe machine.

Fourth, by reason of the peculiar construction of my blocks Z2, I am able to obtain a very delicate adjustment vertically, being at the same time suiciently strong to avoid springing or vibration, and offering, by their construction, no possibilities for an accumulation of cuttings or chips to ii'iterfere with the working.

l. The notched supports f j', mounted in vertical guides in the blocks F1, so that they may yield vertically downward tov any required extent, being pressed upward.by the action of the springs F201' their equivalents, the several parts being adapted to serve, relatively to each other and jro the cutting-mechanism of a milling-machine, substantially in the manner and for the purposes set forth.

2. The cams -1 and their o eratinU-means in oom-y bination with the yielding supports f f, all adapted to Y serve, in relation to each other and to the clamping and cutting-inechanismin a knife-edge milling-machine, substantially as and for the purposes herein set forth.

3. The springs K1, arranged, relatively to the clamps or cross-pieces H and to the supports G of a millingmachine, substantially as herein described 4. rlhe blocks Z2, mounted, as representech'on the screws Z1, and adapted to serve as represented, relatively to each other and to the cutting-mechanism of a milling-machine, for the purposes herein set forth.

' In testimony whereof, I have hereunto set my name, in presence of two subscribing witnesses.

' THOS. J. ROCKWOOD.

Witnesses:

W. 0.DEY,

C. G. LIvINes. 

